The deposition of a benefit agent onto a substrate, such as a fabric, is a well known method of imparting desirable properties to the substrate. In laundry applications the range of “benefit agents” is diverse and includes fabric softeners and conditioners, soil release polymers, shape retention agents, anti-crease agents, ease of ironing aids, perfumes, lubricants, texturising agents, insecticide repellents, fungicides, photofading inhibitors, fluorescers, sunscreens and many others. Deposition of a benefit agent is used, for example, in fabric treatment processes such as fabric conditioning to confer, for example, softening benefit to the fabric.
Conventionally, the deposition of the benefit agent has had to rely upon attractive forces between the oppositely charged substrate and the benefit agent. For example, cotton is negatively charged and thus requires a positively charged benefit agent in order for the benefit agent to be substantive to the cotton, i.e. to have an affinity for the cotton so as to absorb onto it.
However, adverse charge considerations can place severe limitations upon the inclusion of benefit agents in compositions where an active component thereof is of an opposite charge to that of the benefit agent. For example, cationic fabric conditioning agents are incompatible with anionic surfactants in laundry washing compositions, hence fabric conditioning products are usually separate from main wash products. Furthermore, the substantivity of the benefit agent can be severely reduced and/or the deposition rate of the benefit agent can be reduced because of the presence of incompatible charged species in the compositions. The conventional way around this problem is to add benefit agents during the rinsing step of a treatment process so as to avoid adverse effects from other charged chemical species present in the main wash compositions. This has clear cost disadvantages to the consumer and instigates the need for two separate products instead of one.
However, in recent times, it has been proposed to deliver a benefit agent in a form whereby it is substituted onto another chemical moiety, which itself has an affinity for the substrate in question.